Currently, display device are becoming thinner, lighter, higher in resolution, narrower in frame and more energy-saving, therefore it is necessary to integrate more switching elements and smaller pixels into a limited space to meet requirements of the display devices. In order to avoid increasing processing steps and a manufacture cost, generally a Gate Driver on Array (GOA) technology is employed to integrate gate driving units on an array substrate to form GOA units. In the GOA, as a gate driving technique, usually shift registers are used to implement a scan driving.
During implementing the above-described scan driving, the inventor found that the prior art has at least the following problem. For example, the shift register with a structure illustrated in FIG. 1 comprises first to six thin film transistors M1′ to M6′, which are all P-type thin film transistors, and a first capacitor CF, and an enable level of the thin film transistors is a low level (The enable level of the thin film transistor refers to a level at which the thin film transistor is turned on. For example, the low level may control the P-type thin film transistor to turn on, so the enable level of the P-type thin film transistor is the low level; and a high level may control the P-type thin film transistor to turn off, so a disable level of the P-type thin film transistor is the high level). As illustrated in FIG. 2, during a first phase T1, the low level is inputted to a first node A′ and the high level is inputted to a third node C′; during a second phase T2, the high level is inputted to the first node A′ and the third node C′; during a third phase T3, the low level is inputted to the first node A′ while the third node C′ is floated and maintains at the high level; and during a fourth phase T4, the first node A′ is floated and maintains at the low level, meanwhile the fifth thin film transistor M5′ is turned on so that a potential remaining at the third node C′ interferes with the first node A′, which in turn may affect an on state of the sixth thin film transistor M6′, causing the shift register to have a drifting phenomenon at a pulling-up voltage, and resulting in unstable output signals and in turn leading to unreliability in operations of the shift register.